Dosun Fuwari

Dosun Fuwari is a Nikoli puzzle in which the aim of the game is to place white circles (balloons) and black circles (iron balls) in all rooms on a grid, while accounting for gravity.
Dosun Fuwari can be played on any grid size, but the bigger the grid the bigger the challenge, at least in most cases.

The rules are as follows:
- Place balloons (white circles) and iron balls (black circles) in each room on the grid.
- Balloons float to the top, so they must be placed either at the top of the grid, under a black cell, or under another balloon. Rooms don't have a ceiling, so a balloon will continue to float into other rooms if there's space above it.
- Iron balls drop to the ground, so they must be placed either at the bottom of the grid, on top of black cells, or on top of other iron balls. Rooms have no floors, so an iron ball will continue to drop into other rooms if there's space below it.

Standard version

Dosun Fuwari's usually an easy puzzle to solve, but bigger grids with bigger rooms can pose a decent challenge. The smaller the room the less possibilities, so these rooms are usually the best place to start. Other good places are the top rooms for iron balls and the bottom ones for balloons. The gravity rules allow for more opportunities of deduction in these areas, whereas the middle bits often depend on the placements of balloons in the top, and iron balls in the bottom.

Converting it to an RPG setting.

Dosun Fuwari offers little variety in adaptations. While the gravity element could be replaced with left and right flowing forces, the overall themes tend to be the same. It can definitely make for a fun puzzle if you theme it with floating and heavy set creatures or inanimate objects. They could even be used to build a path alongside a wall, but this does require some careful planning, especially if you don't want to give the answer away immediately, as paths are often easy to find.
Alternatively you could turn it into a jumping puzzle type of path, perhaps the characters even have to hold onto the balloons to get them to higher bits.

For my example I went with a more literal adaptation. My character is faced with a wall containing 6 marked segments. She's told to put a balloon and anvil in each of them, but there are no floors or ceiling to prevent the anvils and balloons from dropping and floating further. She is told balloons will block other balloons, and anvils will block other anvils.

Should she succeed in putting a balloon and anvil in each room she'll unlock a secret room. Should she fail to do so the secret room will forever be lost to her, including whatever loot or other secrets awaited her there.

If you do want to get a little more creative with your adaptation, try thinking in an extra dimension. In the standard version you only think about up and down, but backward and forward could make for interesting elements too.
A dam with leaks that need to be blocked by the 'balloons' and 'iron balls', arrow shooting traps that can be blocked, security cameras whose vision could be blocked, and so on. There's plenty to play with, especially in terms of making the puzzle fit the story universe.